Microwave properties of single-walled carbon nanotubes films below percolation threshold

Abstract

A film residue obtained by evaporating surfactant-stabilized single-walled carbon nanotube (SWNT) suspension was characterized at 12 GHz using a scanning-sample dielectric resonator technique. Resonant frequency and quality factor changes were measured and cavity perturbation method was used to calculate the SWNT complex permittivity. The effective permittivity of the SWNT was determined as (3516-j316.5), which provided an average dielectric constant and conductivity for a single SWNT to be 8.1×105 and 8.4×106 S/m, respectively. Microwave induced losses originated only from the electric field, not from the magnetic field, thus indicating an absence of direct electrical contact between nanotubes and a below percolation-limit configuration.